1. Field of the Invention
The present invention is generally related to determining an intensity profile along an illuminating beam and, more particularly, to an apparatus and method for the direct measurement of a variable vertical intensity profile through a plane of focus and hence a determination of a depth of a focal plane and a maximum intensity of the intensity profile.
2. Description of Related Art
There are a multitude of applications where it is desirable to determine an intensity profile or degree of focus through a plane of focus or a plurality of different focal planes. In one instance it is measure properties of a sample via a confocal microscope. The roughness of a surface, the curvature of the surface and the height of ‘steps’ on the surface are typical applications for a confocal microscope. In biomedical research, there is tremendous growth in the use of confocal microscopy. However, there is a need in the art for a more precise means to aid in determining the distance between the cells in a tissue, or organelles in a cell being observed using the confocal microscope.
Another rapidly growing area in the semiconductor industry, is the use of ‘bumps’ or other three dimensional features that protrude outwardly from the wafer or substrate. The manufacturers, processors, and users of such wafers or like substrates having bumps or other three dimensional features desire to inspect these wafers or like substrates in the same or similar manner to the two dimensional substrates. The manufacturers of semiconductors have made vast improvements in end-product quality, speed and performance as well as in manufacturing process quality, speed and performance. However, there continues to be a demand for faster, more reliable and higher performing semiconductors. However, many obstacles exist, such as a significant height of bumps or the like, which causes focusing problems, shadowing problems, and general depth perception problems. A further need exists in the area of three dimensional imaging, wherein the three dimensional image is constructed from a plurality of image taken at differing focal planes. Many of the current systems, devices, apparatus and methods are either completely insufficient to handle those problems or cannot satisfy the speed, accuracy, and other requirements.
Thus, an unaddressed need exists in the art to overcome the aforementioned deficiencies and inadequacies.